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Horizontal CO2 Reactor - Yugang 鱼缸 Reactor

  • Thread starter Thread starter Yugang
  • Start date Start date
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However, that's part of what's so appealing for me about using Regulator mode. I have really nice custom regulators with good needle valves, and flowmeters to measure the actual rate of CO2 injection in SCCM.

Because 100% of my CO2 gets dissolved with regulator mode, I know that if my flow meter is at 30sccm, ALL 30sccm of CO2 is being injected into my tank at all times while active...
Well, presumably your flowmeter would still be active measuring the co2 flowing into the horizontal reactor when you are using the reactor in overflow mose wouldnt it? If you turn up the flow so a little gas bubbles out of the reactor every minute or so, how much more co2 is the flowmeter reading? And if gas is flowing out of the outlet every 30 seconds?
 
Any chance you could provide details on that fitting that allows your CO2 tubing into the reactor? I've been trying to build a PVC version of this too but I'm losing my mind trying to find how to get a 6mm OD 4MM ID tube cleanly into the reactor.
I simply use a threaded airline valve as used when setting up airline drops in a whole fishroom air supply.

I predrill a hole in the pvc pipe, chuck the airline valve into the drill chuck and install it into the pvc pipe.


Standard co2 line attaches nicely.


IMG_1143.webp

IMG_1147.webp



.

$15.88 for 20 valves. I am set for life…
 
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I’d seen some PVC examples here but wanted something that had the ability to be taken apart for cleaning and such.
Well, if you have a desire to clean a standard pvc diy reactor it is easy to cut the pipe and you can clean the inside. It can then be reassembled using a neoprene sleave with stainless hose clamps. Ie a fernco coupler. Used in plumbing all the time. Very waterproof and rigid once applied.

A pair of Fernco couplers could allow you to substitute longer or shorter pieces of intervening pipe to increase or decrease the capacity of the reactor.

For myself I have no compulsion to clean the interior of my reactor.
 
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Well, presumably your flowmeter would still be active measuring the co2 flowing into the horizontal reactor when you are using the reactor in overflow mose wouldnt it?
Of course! But it loses its helpfulness when the SCCM doesn't mean anything specifically due to overflow mode. Does 30sccm in the morning get 100% injected, while 30sccm in the afternoon only gets 70% injected due to the afternoon overflow mode?
If you turn up the flow so a little gas bubbles out of the reactor every minute or so, how much more co2 is the flowmeter reading? And if gas is flowing out of the outlet every 30 seconds?
I'll have to test if/when I switch it up!
 
Well, if you have a desire to clean a standard pvc diy reactor it is easy to cut the pipe and you can clean the inside. It can then be reassembled using a neoprene sleave with stainless hose clamps. Ie a fernco coupler. Used in plumbing all the time. Very waterproof and rigid once applied.

A pair of Fernco couplers could allow you to substitute longer or shorter pieces of intervening pipe to increase or decrease the capacity of the reactor.

For myself I have no compulsion to clean the interior of my reactor.
@scaperhynes you can also use Union couplings. They're basically quick disconnects for PVC piping.
Will allow you to at least remove/open your reactor. Come in different sizes so you can put one large on in the middle to allow you to easily open it if necessary just by unscrewing the middle
 
I just posted an article "Yugang CO2 Reactor - A Guide".

Going forward, I will edit and update the article, with new insights and perhaps add a trouble shooting chapter. When kept up to date, I hope this resource will make it much easier to understand the concepts and operation, and without having to go through all 425 posts in this thread.

I attach a pdf document, for those who prefer to have a printable and offline version.

I hope this is helpfull.

1757937968536.webp
 

Attachments

Last edited:
I just posted an article "Yugang CO2 Reactor - A Guide".

Going forward, I will edit and update the article, with new insights and perhaps add a trouble shooting chapter. When kept up to date, I hope this resource will make it much easier to understand the concepts and operation, and without having to go through all 425 posts in this thread.

I attach a pdf document, for those who prefer to have a printable and offline version.

I hope this is helpfull.

View attachment 10366
1757944865253.webp
 
For anyone else struggling to find where to buy clear pipe and the appropriate fittings for building one of these Yugang reactors DIY, hopefully this will save you all some time and work.

I'll be making a journal at some point about this build that this belongs to, but no commercially made reactors would even remotely fit in my stand so I decided to build this per the guidance of @Jeff Miotke .

Please make sure to select a pipe length appropriate for your tank per: Yugang CO2 Reactor - A Guide

As per Yugang's guide, clear pipe isn't strictly necessary, but I find it helpful to get the system purged and such. I found clearpipe.com's prices to be fairly reasonable and it's great that you can get it cut to length for renters like me without access to a saw.

To save you further time - The reducer couplings and clear pipe are very uncommon to find at your local hardware store so online is the best place to go. Unfortunately this does mean shipping will add to the cost shown in the bill of materials. 2" Pipe is the sweet spot of cost for the clear pipe and fittings, anything larger than that in diameter gets expensive very quickly.

Getting a grasp on which PVC fittings go together can be a real head scratcher, feel free to PM me with questions if you're altering this design.

For those who are curious, I used a 3D printed bracket to mount my reactor into my cabinet... sorry, I know most don't have access to things like this but I was in a crunch to get this finished and order plants before it gets too cold.

Hope this is useful to someone!


IMG_0861.webp

Screenshot 2025-10-05 at 2.48.39 PM.webp
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IMG_1088.webp
I
 

Hope this is useful to someone!

Eureka 💯💯💯💯 you have found it!!


Outstanding 🏆
 
Just my contribution to the discussion on this forum .......
I have recently put together one of these reactors.

50mm clear PVC pipe
plain PVC end caps
50mm PVC union coupling to enable the reactor to be split in half if ever needed.
brass bulkhead barbed 12mm hose connectors

All glued together with PVC cement. The bulkhead connectors are sealed internally with silicon washers.
CO2 is currently injected just upstream via an inline diffuser with the ceramic removed. However, I think I will be adding a new 4mm bulkhead connector to inject the CO2 directly into the reactor as I am experiencing quite a large remnant bubble of other gases at the end of the day. I forget who but someone else on here reported the same thing which was rectified by injecting directly into the reactor. I will report back to let everyone know if it has the same effect on mine too.

I run the reactor in "overflow" mode.

I have the outlet pipe offset quite a way from centre to enable me to adjust the surface area by simply twisting the reactor, which is easy to do as its all plugged into a flexible hose circuit. Its plugged into a bypass loop in one of my EHeim 2217 outputs. I was not aiming for huge CO2 levels so went for a minimum tank surface area to reactor surface area ratio of around 35. It can be adjusted way more, easily up to around 100 if need be if I want less CO2 absorbtion. Its a 150 gallon tank so the internal reactor length is 52.5cm.

Note - the bypass loop seemed essential as it was way too noisy without it, and also sucked the gas out bigtime with a whirlpool type effect inside the reactor.
I've been running it at maximum reactor surface area for a few days and just tested the tankwater CO2 levels at the end of the "CO2 day" with my brand new Hanna CO2 test kit (a fine bit of kit) and it comes out at 32.5 ppm, so I'm really happy with that. I'll do further testing and fine tuning in the coming days to perfect the CO2 timing cycled. Water is of course crystal clear !!
Heres some pics. PLus a rough and ready snap of the tank. You'll see that my work is not laboratory engineer standards of neatness etc, but it does all seem functional !........
IMG_6754.webpIMG_6759.webp
IMG_6761.webpIMG_6769_edited-1.webpIMG_6777 (1).webp
 
Another source for thin acrylic pipe 👍


some glue that is supposed to bond acrylic to the PVC end caps

Be interested to know what is this glue, and has it worked for you?
 
Another source for thin acrylic pipe 👍




Be interested to know what is this glue, and has it worked for you?
I purchased Weld-On #16 Acrylic cement . It's solvent based and did react as a solvent on both surfaces. I've glued one end cap to the pipe and while I have yet to do any kind of water pressure test, it does seem like a solid bond. It seems expensive but it is very thin so I think the 5 oz tube will go a long way. The thinness is also a drawback though, as it makes it messy to work with. In fact, as soon as you remove the cap, it will want to squirt out.
 
Awesome work!
Note - the bypass loop seemed essential as it was way too noisy without it, and also sucked the gas out bigtime with a whirlpool type effect inside the reactor.
This can be avoided by using a reactor with a larger diameter -- smaller diameter might make splashing/rushing noises louder.
In fact, my perfect "dream" reactor has an offset inlet similar to the offset outlet -- to "introduce" incoming water a low in the reactor as possible. The ARC Stainless Steel reactor is like this, I believe.
Still, if you don't mind managing a bypass to clear any large gasses every now and then, you're good!
I've been running it at maximum reactor surface area for a few days and just tested the tankwater CO2 levels at the end of the "CO2 day" with my brand new Hanna CO2 test kit (a fine bit of kit) and it comes out at 32.5 ppm, so I'm really happy with that. I'll do further testing and fine tuning in the coming days to perfect the CO2 timing cycled. Water is of course crystal clear !!
Don't forget to test the beginning of the day! It's really more important what your CO2 ppm is when the lights come on -- ideally, you'd want to have the CO2 ppm be at/near your target when the lights come on, and maintained about that through the day, like these two images:


1759872015271.webp



1759872019140.webp

Sometimes with a horizontal reactor, all it takes is moving your CO2 timer "up" a few hours.
 
Don't forget to test the beginning of the day! It's really more important what your CO2 ppm is when the lights come on -- ideally, you'd want to have the CO2 ppm be at/near your target when the lights come on, and maintained about that through the day, like these two images:

Yup, on my radar. I literally only received the Hanna test in the mail yesterday. I am already busy testing the rate of the dissolved CO2 rise this morning. 2 hours in and its up to 20 ppm. I had the timer set to switch CO2 on 3 hours before lights on and it looks like that's going to be just about right.
It really is a great test. thankyou for the recommendation as it was the main reaosn I bought it. Having a near zero dKH tank measuring pH drop is problematic and we all know about the issues with drop checkers, which would be virtually useless for me. This test is exactly what I needed.

Edit - tank seemed nicely degassed before CO2 switch on - at around 5 ppm CO2.
1 hr CO2 - 12ppm
2 hrs CO2 - 20 ppm
2.5 hrs CO2 - 25 ppm

So, it looks like a 3 hr CO2 build up period before lights on will be pretty perfect, keeping dissolved CO2 levels in the high 20's/low 30's for the key lighting period. I need to now do a similar thing at CO2 "off" to see how quickly dissolved CO2 levels drop.
 
Last edited:
I just posted an article "Yugang CO2 Reactor - A Guide".

Going forward, I will edit and update the article, with new insights and perhaps add a trouble shooting chapter. When kept up to date, I hope this resource will make it much easier to understand the concepts and operation, and without having to go through all 425 posts in this thread.

I attach a pdf document, for those who prefer to have a printable and offline version.

I hope this is helpfull.

View attachment 10366
Hi, I have a question about the overflow. The gases dissolved in the water that accumulate in the bag will be mainly oxygen and nitrogen, gases that are lighter than CO2. In this case, the CO2 is positioned at the bottom of the bag, and consequently, during the overflow operation, the CO2 will be the first to exit, with the consequence that sooner or later the bag will be saturated with other gases and the system will stop working. Is this correct? Thanks.
 
For anyone else struggling to find where to buy clear pipe and the appropriate fittings for building one of these Yugang reactors DIY, hopefully this will save you all some time and work.

I'll be making a journal at some point about this build that this belongs to, but no commercially made reactors would even remotely fit in my stand so I decided to build this per the guidance of @Jeff Miotke .

Please make sure to select a pipe length appropriate for your tank per: Yugang CO2 Reactor - A Guide

As per Yugang's guide, clear pipe isn't strictly necessary, but I find it helpful to get the system purged and such. I found clearpipe.com's prices to be fairly reasonable and it's great that you can get it cut to length for renters like me without access to a saw.

To save you further time - The reducer couplings and clear pipe are very uncommon to find at your local hardware store so online is the best place to go. Unfortunately this does mean shipping will add to the cost shown in the bill of materials. 2" Pipe is the sweet spot of cost for the clear pipe and fittings, anything larger than that in diameter gets expensive very quickly.

Getting a grasp on which PVC fittings go together can be a real head scratcher, feel free to PM me with questions if you're altering this design.

For those who are curious, I used a 3D printed bracket to mount my reactor into my cabinet... sorry, I know most don't have access to things like this but I was in a crunch to get this finished and order plants before it gets too cold.

Hope this is useful to someone!


View attachment 10772

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I
Hello, connector number 12 is a pneumatic connector, meaning they work in a pressurized system. In this reactor, the CO2 comes out without pressure. Is the seal still guaranteed? Both with the system on, for possible CO2 leaks, and with the system off, for possible water infiltration. Thank you.
 

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